Marcelo B. Pisani

Dual-beam actuation of piezoelectric AlN RF MEMS switches monolithically integrated with AlN contour-mode resonators

This work reports on piezoelectric aluminum nitride (AlN) based dual-beam RF MEMS switches that have been monolithically integrated with AlN contour-mode resonators. The dual-beam switch design presented in this paper intrinsically compensates for the residual stress in the deposited films, requires a low actuation voltage (5 to 20 V) and facilitates active pull-off to open the switch and exhibits fast switching times (1 to 2 µs). This work also presents the combined response (cascaded S parameters) of a resonator and a switch that were co-fabricated on the same substrate. The response shows that the resonator can be effectively turned on and off by the switch. A post-CMOS compatible process was used for the co-fabrication of both the switches and the resonators. The single-chip RF solution presented constitutes an unprecedented step forward towards the realization of compact, low-loss and integrated multi-frequency RF front-ends.

Application of Micromachined

This paper presents the design, fabrication, and characterization of thermal infrared (IR) imaging arrays operating at room temperature which are based on Y-cut-quartz bulk acoustic wave resonators. A novel method of tracking the resonance frequency based upon the measurement of impedance is presented. High-frequency (240-MHz) micromachined resonators from Y-cut-quartz crystal cuts were fabricated using heterogeneous integration techniques on a silicon wafer. A temperature sensitivity of 22.16 kHz/°C was experimentally measured. IR measurements on the resonator pixel resulted in a noise equivalent power of 3.90 nW/Hz1/2, a detectivity D* of 1 × 105 cm · Hz1/2/W, and a noise equivalent temperature difference of 4 mK in the 8- to 14-μm wavelength range. The thermal frequency response of the resonator was determined to be faster than 33 Hz, demonstrating its applicability in video-rate uncooled IR imaging. This work represents the first comprehensive thermal characterization of micromachined F-cut-quartz resonators and their IR sensing response.

Y

This paper reports experimental results on a new class of single-chip multi-frequency channel-select filters based on self-coupled aluminum nitride (AlN) contour-mode piezoelectric resonators. For the first time, two-port AlN contour- mode resonators are connected in series and electrically coupled using their intrinsic capacitance to form multi-frequency (94 -271 MHz), narrow bandwidth (~ .3%), low insertion loss (~4 dB), high off-band rejection (~60 dB) and extremely linear (IIP3-110 dBm) channel-select filters. This novel technology enables multi-frequency, high-performance and small form factor filter arrays and makes a single-chip multi-band RF solution possible in the near future.

-Cut-Quartz Bulk Acoustic Wave Resonator for Infrared Sensing

The paper proposes and validates a new doubly functional quartz wafer-level package concept for MEMS devices. In addition to the mechanical and environment protection, thick-Cu high-Q inductors for RF applications are made within the package processing. A double-side processing of a quartz wafer is reported. While the top side of the quartz is used to realize quartz-embedded horizontal plane Cu inductors, the bottom side is thermo-mechanically bonded on an active wafer using an SU8 photoepoxy semi-hermetic seal. A successful fabrication results in terms of very good adhesion of SU8 bonding, compatibility with fluorine plasma chemistry for MEMS release and very good RF performances (excellent quality factors, higher than 30 at 2 GHz, and self resonant frequency above 6 GHz) was demonstrated

12E-3 Channel-Select RF MEMS Filters Based on Self-Coupled AlN Contour-Mode Piezoelectric Resonators

This paper presents the design, fabrication, and characterization of temperature sensitive quartz resonators fabricated using heterogeneous integration methods for realizing high-density, thermal conductance fluctuation limited thermal sensors for infrared imaging and biochemical sensing applications. An integrated quartz sensor array using CMOS-compatible micromachining techniques has been designed and fabricated. 241 MHz micromachined resonators from F-cut quartz crystal cuts were fabricated with a temperature sensitivity of 22.162 kHz/°C. Infrared measurements on the resonator pixel resulted in a noise equivalent power (NEP) of 3.90 nW/Hz1/2, detectivity D* of 9.17 ×107 cmHz1/2/W, and noise equivalent temperature difference (NETD) in the 8–12 µm wavelength region of 4 mK and a response time of < 30 Hz. In a unique new application a remotely coupled thermal sensor configuration was used to monitor biochemical reactions in real time.

High Quality Factor Copper Inductors on Wafer-Level Quartz Package for RF MEMS Applications

The design of distributed amplifiers in a CMOS process is investigated. In particular, the impact of parasitic elements from the transistors and from interstage inductors is studied. A methodology for determining an optimum design, including the number of stages, without needing a complete inductor model at the outset, is presented. This proposed methodology reduces the time and complexity of a distributed amplifier design while at the same time allowing the designer to gain more insight into the circuits behavior.

Micromachined quartz resonator-based high performance thermal sensors

This paper reports on the fabrication and application of Y-cut temperature-sensitive quartz resonators for infrared detection applications. The high thermal sensitivity of the Y-cut quartz crystal (90 ppm/K) and the high quality factor (≫10,000) of the piezoelectric bulk acoustic wave resonators fabricated from such crystals enable the application of these devices as extremely sensitive uncooled thermal infrared (IR) detectors. We report the fabrication and performance of inverted mesa devices with 1 mm diameter and 18 µm thickness with 6.8 kHz/K of temperature sensitivity at 90 MHz.